It would work as intended? I’m not sure what problem you are trying to point out. The lambda would compile in the edition in which it is written, resulting in a

It would work as intended? I’m not sure what problem you are trying to point out. The lambda would compile in the edition in which it is written, resulting in a code unit passed to the other crate(s). As mentioned, the ABI is stable across editions. To put in your words, there are no semantic changes to the ABI across editions.